With a ~lot of~ little help from a friend at xda I managed to get my device to boot an engineering rom. Would love to give this version a run, but the xda link provided in your post points to an abandoned rom and the recovery linked there leads into a 404.
Flash The Provided Recovery From Fastboot
Inside The Recovery, Wipe - Metadata, Data & Cache
Flash The Rom Using Sdcard Or Sideload Using ADB
Format Data
Reboot To System
Update installation:
Reboot To Recovery
Flash The Rom Using Sdcard Or Sideload Using ADB
Wipe Cache Inside Recovery
Reboot To System
you can just boot to recovery without flashing it : fastboot boot recovery.img instead of fastboot flash boot recovery.img
I would not recommend, however, flashing TWRP! It bricked my phone and I had to resort to professional help to even get it to open fastboot again! (Apparently TWRP somehow messed with some partitions inside the phone so it wouldn‘t boot anything anymore. See my xda thread here: Thread ‚Help needed - unbrick via mtkclient‘)
I‘ll try to find the boot.img inside the payload. So far I haven‘t been able to successfully do so via payload dumper.
Are you positive that this boot.img works as intended? Why would @ronnz98 always link to other builds (and their respective recoveries) over at xda when publishing here?
Sorry for all the fuzz, simply hoping to provide guidance for people in the same spot.